1. Field of the Invention
The invention relates to a cooling structure of a cylinder block, and more particularly to a cooling structure of a cylinder block in which foreign matter can be captured.
2. Description of the Related Art
A cooling structure of a cylinder block is disclosed, for example, in Japanese Patent Laid-Open Publication No. 2002-30989.
In the cooling structure of a cylinder block disclosed in the Japanese Patent Laid-Open Publication No. 2002-30989, the temperature of a bore wall is made uniform by providing a water jacket spacer inside a water jacket portion of a cylinder block of an internal combustion engine. However, when the water jacket spacer is installed, a processing burr on an upper surface of the cylinder block may be cut off and may fall into the water jacket portion. The burr that has fallen into the water jacket may damage a mechanical seal of a water pump, which leads to water leakage, and a decrease in reliability.